Just got back from the dealership. Finally, feel like I may have some answers. The tech took my 4R for a lengthy test drive (about 15 miles). Varied driving, including highway (up to 80), stop and go traffic and cruising between 40 and 50 (where I notice the problem). He wasn't able to get it to replicate the "shudder".

Couple of things he mentioned, first is the way the tranny locks up. He said the lock-up pattern has changed (for fuel economy reasons) and that can actually happen at any speed. When the lock-up occurs that might be when I notice the shudder. He also said, depending on the type of car I previously owned that it might seem more noticeable. He also said that the way the power is transferred from the engine to the transfer case can feel like there is play in it..I call BS on that..I've driven plenty of 4wd vehicles and play in the driveline is not even remotely close to a shudder.

Another thing he noticed was that I was driving with the Hum device plugged into my OB2. He suggested the Hum might potentially be causing interference with the CAN-BUS because it's constantly communicating back and forth with the controllers in the vehicle that provide diagnostics. It seems plausible, so I unplugged the Hum device and will see whether that makes a difference.